Signal processing in an optical correlation reflectometer using fragments of the M-sequence for probing a fiber-optic path

In an earlier work, the possibility of using a combination of M-sequence fragments with varying initial phases for probing a fiber-optic path was considered. The proposed method makes it possible to record the reflectogram of a fiber-optic path with high accuracy, but when it is implemented, the required memory volume increases significantly and the amount of computations increases significantly, due to the need to carry out correlation processing of the backscatter signal from each fragment of the M-sequence separately, and after processing it is necessary to carry out the operation of summing all the obtained autocorrelation functions. In this paper, we consider the use of a circular memory register to reduce the amount of memory occupied by the reflectometer and the number of computational operations. It is proposed to record backscatter signals from each fragment of the M-sequence into one common circular register, and then perform correlation processing of the entire data array at a time using a reference signal in the form of a complete M-sequence.